General sales don't start until June 9th, but if you've signed up to Mirvish's newsletter then you'll have seen this in your inbox today;
If you'd rather speak with a person (or if you're an international buyer and can't use the website - not sure about the Mirvish but I know I had to call Tuacahn to book my tickets last year and when I went to see The Little Mermaid in Denver during its preview run) then the numbers to call are 416-872-1212 and 800-461-3333 and quote "Mirvish".
I hope everyone gets the tickets they want! These are exciting times, hopefully casting news is just around the corner now (still crossing my fingers for as much of the original cast as they can get back!)